Shinjiro, who runs a humble detective agency using a coffee shop in a certain town as his office, gets into trouble at a dark gambling den and is forced to take on a troublesome job by Kyoichi, an executive of the Kasahara clan, a yakuza gang he knows well. The task is to investigate an arson case that is suspected to involve the Chinese mafia Barretto, with whom the Kasahara-gumi has a rival gang. In addition, Shinjiro is asked by Michiko, whose Filipino parents were deported in the past, to search for her best friend, a Kurdish woman who mysteriously disappeared. However, as he pursues the two cases, he finds himself caught up in a war between two huge underworld organizations.